A pneumatic system having a central air compressor is used to simultaneously provide pressurized air to two pneumatic circuits. The first pneumatic circuit is known as a critical circuit, which provides pressurized air to critical components, and the second is commonly referred to as an auxiliary circuit, which serves auxiliary components. If a leak or catastrophic failure occurs in one of the circuits, air pressure may be reduced in the critical circuit to below minimum operating parameters, thereby causing the loss of operation of critical components. To mitigate this effect, a pressure protection valve may be installed between the compressor and the auxiliary circuit. The pressure protection valve, upon sensing a loss of air pressure in the inlet of the pressure protection valve due to a leak or failure in either circuit, will isolate the auxiliary circuit from the compressor, preserving pressurized air for the critical circuit.
Pressure protection valves are particularly used in Class 8 motor vehicles which are manufactured with a pneumatic system that includes a critical circuit and an auxiliary circuit. The critical components served by the critical circuit typically include a primary pneumatic braking system and a secondary pneumatic braking system. The auxiliary circuit typically serves auxiliary components such as an exhaust brake, air horn, or air suspension systems.
However, existing pressure protection valves have various limitations. Existing valves have many components making them expensive to manufacture and susceptible to failures and are often difficult to install and orient to connecting air lines.